IDEAS & TRENDS; My Not-Even-Remotely-Funny Valentine

By KATE ZERNIKE

Published: February 11, 2007

IN Margaret Atwood's story ''Hairball,'' the protagonist has just had a benign ovarian tumor removed when her married lover-boss informs her that she has been fired. When she arrives home to an engraved cocktail party invitation from him and his wife, she knows exactly how to respond. She goes to a fancy food shop and buys a box of chocolate truffles, the kind he gave her after their first tryst. She takes the tumor she has kept as a souvenir, dusts it with cocoa powder, nestles it in the elaborately wrapped box, and sends it to her lover with a note expressing her regrets.

Gruesome, bizarre, the kind of thing only fiction could imagine.

So why, then, is fact so often just as weird?

What novelist, after all, could have dreamed up the diaper that Lisa Nowak, the Navy captain, astronaut and married mother of three, put on so she would not have to stop to go to the bathroom as she drove 950 miles, the police said, to confront the woman she believed stood between her and the object of her affection?

Sure, Hollywood produced a runaway bride, but it took real life -- a 32-year-old Georgia woman who fled west by bus in 2005 -- to give us one who faked her own abduction. Then there's the skydiver detained last month in Belgium after the police said she sabotaged another diver's parachute, then watched her fall 13,000 feet to her death, all because she suspected the woman was having an affair with her boyfriend.

It's a question for the ages, but hey, it's almost Valentine's Day: What is it about love that drives apparently rational people to such blindly irrational behavior?

No question, love reigns supreme in human behavior. ''There's very little in life we desire as much as to be connected with someone we love,'' said Arthur Aron, a professor of social psychology at the State University of New York at Stony Brook. ''It trumps the desire for wealth, for power, even to live. People feel that if only this person would reciprocate, their lives would be just perfect.''

As science has become better able to analyze brain activity, some researchers argue it boils down to chemistry.

Helen Fisher, an anthropologist at Rutgers who has written extensively on love and mating, described a recent experiment in which she and colleagues put 15 people who had been madly in love and freshly rejected through M.R.I. scans. Their scans showed decreased blood to the area of the brain associated with decision-making. But the brains showed increased activity in the dopamine reward system, or what Dr. Fisher called ''the wanting-seeking system,'' associated with craving and taking big risks, as well as in areas associated with physical pain and obsessive-compulsive disorder.

The overall picture was of what Dr. Fisher calls ''abandonment rage.''

''You've got a person who has enormous energy and intense motivation and craving, with focused attention, willing to take huge risks, in physical pain, trying to control their anger, and obsessively thinking about someone,'' she said. ''It's a bad combination.''

Love, in this interpretation, really is the drug.

''If you really want cocaine and you don't have it,'' Dr. Aron said, ''you'll do the same sorts of things.''

Others caution against blaming nature for ''crazy love.''

When someone goes over the edge, it tends to be that they are missing some ability to make moral judgments, or suffering some mental disorder.

Of course, ''being in love is not a mental disorder, thank God,'' said Pamela Regan, a professor of psychology at California State University, Los Angeles.

People suffering an obsession may have developed a faulty attachment style. They grew up with an emotionally distant parent and become preoccupied with securing a close bond with someone else, even if, and perhaps especially if, that person is unavailable.

The documentary film ''Crazy Love'' tells the story of Burt Pugach, who in 1959 became so obsessed with the woman he was dating that he hired thugs to throw lye in her eyes, permanently blinding her. Crazier yet, when he got out of prison, she married him.

BOTH Mr. Pugach and his wife had suffered distant or emotionally harsh mothers. And to Dan Klores, who made the film, it made sense that they wanted to be together; both were intensely afraid of being alone. He saw parallels in Captain Nowak's behavior.

''There was the same type of heightened fear, that skin-chilling fear of, 'I'm going to lose him,' '' he said.

There but for the grace of God go the rest of us. In 2003, when Clara Harris was on trial in Texas for running over her cheating husband with her Mercedes, lawyers had to strike several jurors from the pool because they told of similar experiences.

One woman recalled how she had nicked her husband with a truck after discovering him with another woman. A man recalled how he had been accused of assault after his wife cheated on him.

But most of us don't buy a steel mallet, drive 950 miles and pepper spray someone in an airport parking garage in the middle of the night, as the police say Captain Nowak did.

There is what Dr. Regan called ''a gray area between normalcy and obsession.''

''We don't realize we're being annoying when we e-mail or text-message someone, and oftentimes the objects are not clear in their refusal,'' she said.

But when the rejection is clear, Dr. Regan continued, ''the key thing is, people who have normal mental development realize that heartache happens, it's painful, it's going to hurt, but I'm going to be O.K.''

For Dr. Fisher, it comes down to better impulse control.

''It is my guess that just about everybody on this planet has wanted to stalk somebody at some point, but we contain ourselves,'' she said.

That doesn't mean you can necessarily screen for some flaw that will expose stalking behavior.

''For many people they simply won't be in a situation that stresses them in such a fashion that their normal filtering process is overruled,'' said James Hollis, the director of the Houston Jung Center and the author of ''Why Good People Do Bad Things.'' ''They're lucky, and they may be conscious of what they're doing.''

It is not unlike road rage, he said: ''It's not about someone driving badly, someone cut me off. It hits an old wound: 'They always disrespected me.' What we do is not crazy. It's logical based on the emotional premise from which it's coming. The emotional premise may not be rational. But it's truthful to the person in the moment.''

People in highly competitive environments may not be used to asking for the help that might steer them away from drastic behavior, Dr. Hollis said. And the drive to excel may extend to every area of their lives. ''This is someone who would go to outer space to reach a goal,'' Dr. Aron said of Captain Nowak, who has been charged with attempted murder.

But no one knows for sure yet why Lisa Nowak behaved as she did. And highly accomplished people -- men or women -- are no more or less prone to such behavior. As Dr. Fisher said, ''Any police blotter could tell you this isn't just astronauts.''